Friction grip for drilling machines



Nov. 22, 1932. I I

A. HOSSFELD FRICTION GRIP FOR DRILLING MACHINES Filed A ril 20. 1932 Ska ing heat will soonroughen the contacting Patented Nov. 22, 1932 "QAL BE RT ,nossnnnn, or wmom;mw oaxgi,

m filedDeceinber: 4, 1931 under Serial Number imicrroncnrr 'ron mam ivracnrnns a 'i Application iil ed'hpril 2 My-present invention relates to friction grip for drilling machines of the type disclosed andfbroadly claimed in my pendingv 7 v p I aonthe line3 --3-ofFig.-'2;-

United States application for Letters Patent 578,883. V I 1 r r It has been found that friction grips for the above use, when made entirely of iron, soon crystallize and break due to the terrific 0 force and speed at which the drill is operated;

'It hasalso been foundthat an all metallic of a drill during the reciprocatory movement of the drill, due to theweight and inertia of the grip, thus producing rapid wear between the metal to metal contact of the parts and the almost constant friction between said parts will produce a high degree ofheat. This wear on th'e'rod ofa" drill-soon changes 0 the shape of the rod so that it does nothave a constant diameter, and hence, the grip, will not engage the same at all points with'the same pressure. Furthermore, this :wear between adrill rod and the grip and the resultsurfaces of therod and the grip to such an extent that they will freeze. and thereby interfere with the feeding of the drill through the grip. The object of the present inventionis to provide a simple andhighly efiicientfriction grip of lighter weight than iron-so that the weight and inertia of the grip will not shift said grip on a drill rod during the reciprocatorymovement of the drill thus eliminating excessive wearfand heat and preventing the grip from crystallizingand breaking.

To the above end, generally stated, theinvention consis ts of the novel devices and combinations of devices hereinafter described and defined in the claims. a

, Inthe accompanying drawing, whicli illusduring the TeciprQ-camry movement Oi the carriage 9, by connections QO -frOn said-beartrates the invention, like characters indicate likeparts throughout the several views.

Referring to the drawing: i

t Fig. 1 is a fragmentary perspectiveyiew of a drilling machine having the improved friction grip embodied therein;

"Fig. 2 is a side elevation ofthe improved fri fioliflgiii; and galear tithe ime or shank,yon'anienlargedscale;J; i'. 1

Fig.3 is a view princ pallyin Fig-4 a exnen e a l PF some parts sectioned onthe line t t oflEig. g 2,.and with the respective bolt removed," r

. Fi-ggfi is a perspectlve view of oneaofithe blocks looking at the inner-(face thereofgrand I .fiFigr 6'is aperspectiveview of oneoflthie f9 resilient members removed from the grip, grip. will shift'bodilyon the rod or shank V trated in the :drawing is fully shown-,Mde-

scribed and broadly claime inthe applica- B5 The, drilling ,machi-ne fragmentarily ill-us- .tion heretofore identified.

Of the parts of the;f,dri -lling shown, it is important to notethedrillfi, the

mainframe 8, carriage -9,,the; tilting frame 10, the-connecting rods 11,-f0r reciproroun-d steel rod and a cutter 15 on one end of :said bo,dy'. ,l ,Thisfdrill f7 isfirnounted onthe I a carriage fl'forcompound reciprocating and rotary movements. -.A pair; of laterally spaced cross-tie plates 16 which form ,a part of the tilting frame 10 support, a striker plate 117 The two spring 12 and 13, which encircle as the drill .body'l l, engage .oppositeends ofthe carriage9 as ,bases of resistance inner ends are axially spaced.

and their The improvedfriction ;-gri p-18,,wis the a i subject imatter of a this, application, is Amount 1185' 7 ed on the drill body 14' between -'-th Springs 12 and 1,3,.normally rests on thebniferspring '13 and supports the drill therefromwiththe V -grip, 18 above the striker plate 17. and;nor-

inally out of contact therewith. The pro-x q pel'l-ing spring 12 is '-.secured to a rotatable bearing 19-on the carriage 9 Jand'oscillated,

ing-to the tilting frame 1.0.:-

{The operation of the improved drillingmachine may be briefly, described as follows, to wit: The upward movement of the carriage i 9 gives the drill 7 a powerful-' throw upward 1 through the medium of theubufier spring 113 a acting on the grip :18 and the force of this '18thereon.m a t p movement of the carriage 9; gives the drill 7 a powerful downward throw v v 21 on the drill body 14;- The bolts '25 clamp "the block s'21 onto the drill body 14 with sufplate 17 and as the drill 7 advances intothe upward throw, whichfcauses the drill 7 .to travel at a faster speed than the carriage 9,

is caught. and absorbed the propelling I spring 12 which is compressed and placed undertension under the action of thegrip Downward that is accelerated by the'expansion 10f the compressed propelling spring 12 "which causes the drill 7 to attain-a high velocity.

At or practically at the end of thedownward stroke of the drill 7 the grip 18-is brought to .a stop .LbyQitsJengagement. with the striker rock it drivesiits'elf through theg'rip18 by the F'fQi'Ce of its-momentum; The feeding of the drill 7 through the grip 18 takes place at jafseries' 'of almost: imperceptible j steps ofv m v m -a a o V For*the purpose of this case, it is not j ithought necessary to describe in detail the V rotary movement imparted to thedrill7aby the aetionofthe'vpropellingspring on the grin*18.'

' Atthe outer faceof each block 21 is a metallic face plate 23 and finterposed between each block 21 audits face plate 23 is a relatively x-thick resilient member 24 of'rubber or other i V suitable-res ilienti material. A-pair of'b'olts [251 equipped with nut-s '26 extend-through V E aligned holes in the blocks 21, resilient memlithe holes in the blocks 21 are of such diarndeter as to leave clearance between said bolts andblocks and; permit slight angular movement of'theibolts 25 with res ect to the blocks ins! surfaces 127.7

sfBv referenceito 3 it will be: noted that 1 21;] The object of this angular movemlent' of ithe bolts 25 .and'the provision of the ball and Referring now in detail to'thefriction' grip; Y 18 the same includes apair of laterally spaced -blocks'21 of wood or other'non metallic material that is lighter 'th an: iron. These blocks 2l-have in their opposing faces'half"seats 22.

time the body 14 through mounted in recessed seats 29 in the oposing faces of the vblocks 21." Each resilient block 28 is notched at 30 to leave apassageway for the respective bolt 25. These resilient blocks 28 are held under compression bythe blocks 21 ancl the object thereof isto separate the blocks 21 when the nuts 26 are turned: on the bolts 25 to reduce the pressure of the blocks onto the drill body 14 and. compensate for 'any'slight variation of'the'diameter of'said body; This frictionallcontact between the 'ga grip 18 and the drill body 14'issuflieienttoj overcome the inertial and the weight, of the grip 18 andprevent thegrip18froin shifting;" longitudinally on the drill 14'during the. V reciprocatory movement of the drill 7; It990 will thus be seen that'thergripl8 will not 8 move onthe drill body 14 exce t as said grip is stoppedby the striker platejl'lduring the operative stroke of the drill? and=at which i drill body 14 moves through the V stoppedgrip by itsmomentum and atwhich time the-' cutter 15 performs its work,

Itfloften happens 'thatiia 'step' 'f. rotary movement-of the drill .7 will position its cut- 7 5 ter on a high spot on theq stone being cut andhhenceythe" grip -18 will not en'gage'the a striker plate 17, during'this stroke of the drill :7 and hence; there will he no movement of the in drill body 14 through the grip 18f; -Neither will the force produced-by the stopping 1 5 thedrill 'i, by its contact with the work -cause V j the grip 1 8 to move on the drill body 14 and 7 thus prevent wear between the 1 contacting parts.

r From. the above description'it is evident llfl 7 that'the'drillbody 7 and grip18 have no relai 'tive movement except the step, bystep move; ment of the drill body-14 through the grip '18 produced-bythe movement-of thedrill thegrip 18. at the time-said '115 grip is-stopped by the striker plate17, thus sooket surfaces 27 is to permit slight relative shifting movements of the blocks 21 infcase s'aidblocks do nbtengage the striker plate 17 f evenlv" or at the same time, It will be noted eliminating all excessive wear-which at pres o 1 lent takesplacebetween a metallic-grip and [drill body and produced .by "the almost. Icontinuous shifting of the grip on thedrill body?! f that'the face plates 23'are of such width as posed and prevent the faceplates' 23 ;from

' cominp' into'direct contact with the/striker Theinner acesof the plates 23' are 'sl v dished'tohold the resilient members 7 24 thereon but atfthe same time permit said' gi'r What I Clalm 5'? members jtofloat-'durino comnressi on thereof.

Inter osed between the blocks 21 andsubstantially' surrounding each bolt 25 is a resilcaused by the weight and inertia of the grip at the time the reciprocating carriagereverses'its 1. A friction griplgin'oluding stair r let i Y rally spaeed blocks having cooperatinghalf.' seats intheir opposing-faces,

a pair of face- I the heads and nutsof the bolts and the face i plates outward of the blocks, a resilient member interposed between each block and its face plate, and a pair of nut-equipped bolts extending through aligned holes in the blocks and the face plates said holes being of such diameter as to permit free angular movement of said bolts therein. V.

2. The structure defined in claim 1 in which plates have ball and socket bearing surfaces.

3. Afriction grip including a pair of laterally spaced blocks having cooperating half seats in their opposing faces, a pairofface plates outward of the blocks, a resilient member interposed betweeneach block and its face plate, a pair of nut-equipped bolts extending through aligned holes in the blocks and the face plates, and resilient means interposed between the blocks and held under compression thereby. 4:. A friction grip including a pair of laterally spaced blocks having cooperating half seats in their opposing faces, a pair of face plates outward of the blocks, and a compressible rubber member interposed between each. A

block and its face plate, and a pair of nutequipped bolts extending through aligned holes in the blocks and the face plates.

5. A friction grip including a pairof laterally spaced blocks having cooperating half-J seats in their opposing faces, a pair of face plates outward of the blocks, a resilient member interposed between each block and its face plate, a pair of nut-equipped bolts extending through aligned holesin the blocks and face plates, and a piece of sponge rubber interposed between the blocks and held under com pression thereby.

6. A friction grip including a pair of laterally spaced blocks having cooperating half seats in their opposing faces for a drill rod, a pair of nut-equipped bolts extending through aligned holes in the drill blocks and holding the blocks frictionally clamped onto the drill rod, a face plate under the head of at least one of the bolts and adjacent block 1 and an elastic rubber member. interposed between said face plate and block, and resilient means interposedv between the blocks and nor mally held compressed thereby.

In testimony whereofI afiix mysignature.

ALBERT HOSSFELD. 

